How do you test old style pcv ?

I just looked in my 63 service manual and it recommends servicing the valve every 6 months by soaking the valve in carb cleaner and blowing out with air. If the valve is severely plugged it can be disassembled and cleaned the spring height is 9/16". It also says all V8s and the 225 use the same P/N valve but the 170 uses a different P/N.